M. McCann, E. Newell, C. Preston, and K. Forbes, “The Use of Mannan-Oligosaccharides and/or Tannin in Broiler Diets”, Int. J. Poult. Sci., vol. 5, no. 9, pp. 873–879, Aug. 2006, doi: 10.3923/ijps.2006.873.879.